133645 has 4 divisors (see below), whose sum is σ = 160380. Its totient is φ = 106912.

The previous prime is 133633. The next prime is 133649. The reversal of 133645 is 546331.

133645 = 258² + 259².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 546331 = 29 ⋅18839.

It can be written as a sum of positive squares in 2 ways, for example, as 66564 + 67081 = 258^2 + 259^2 .

It is a cyclic number.

It is not a de Polignac number, because 133645 - 2¹³ = 125453 is a prime.

It is a super-3 number, since 3×133645³ = 7161094431933375, which contains 333 as substring.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13360 + ... + 13369.

It is an arithmetic number, because the mean of its divisors is an integer number (40095).

2¹³³⁶⁴⁵ is an apocalyptic number.

133645 is the 259-th centered square number.

It is an amenable number.

133645 is a deficient number, since it is larger than the sum of its proper divisors (26735).

133645 is an equidigital number, since it uses as much as digits as its factorization.

133645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26734.

The product of its digits is 1080, while the sum is 22.

The square root of 133645 is about 365.5748897285. The cubic root of 133645 is about 51.1270700357.

Adding to 133645 its reverse (546331), we get a palindrome (679976).

Subtracting 133645 from its reverse (546331), we obtain a triangular number (412686 = T₉₀₈).

The spelling of 133645 in words is "one hundred thirty-three thousand, six hundred forty-five".